Combine sugar and syrup in a 3-quart pan.,Cook over moderate heat, stirring frequently until mixture boils.,Remove from heat. Stir in peanut butter; mix well.,______,Press mixture in a 9 x 13-inch buttered pan.,Melt chocolate and butterscotch bits together over hot, but not boiling, water (or microwave), stirring until well blended. Remove from heat and spread evenly over Krispies mixture.,Cool. Cut into bars.